Timolol
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| Clinical data | |
|---|---|
| Trade names | Betimol, others[1] |
| AHFS/Drugs.com | Monograph |
| MedlinePlus | a602022 |
| Pregnancy category |
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| Routes of administration |
By mouth, topical (eye drop) |
| ATC code | C07AA06 (WHO) S01ED01 (WHO) |
| Legal status | |
| Legal status |
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| Pharmacokinetic data | |
| Bioavailability | 60% |
| Metabolism | Liver (80%) |
| Biological half-life | 2.5–5 hours |
| Excretion | Kidney |
| Identifiers | |
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| CAS Number | 26839-75-8  |
| PubChem (CID) | 33624 |
| IUPHAR/BPS | 565 |
| DrugBank | DB00373 |
| ChemSpider | 31013 |
| UNII | 5JKY92S7BR |
| KEGG | D08600 |
| ChEBI | CHEBI:9599 |
| ChEMBL | CHEMBL499 |
| ECHA InfoCard | 100.043.651 |
| Chemical and physical data | |
| Formula | C13H24N4O3S |
| Molar mass | 316.421 g/mol |
| 3D model (Jmol) | Interactive image |
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Timolol is a medication used either by mouth or as eye drops.[2][3] As eye drops it is used to treat increased pressure inside the eye such as in ocular hypertension and glaucoma.[2] By mouth it is used for high blood pressure, chest pain due to not enough blood flow to the heart, to prevent further complications after a heart attack, and to prevent migraines.[3]
Common side effects with the drops is irritation of the eye.[2] Common side effects by mouth include feeling tired, slow heart beat, itchiness, and shortness of breath.[3] Other side effects include masking the symptoms of low blood sugar in those with diabetes. Use is not recommended in those with asthma, heart failure, or COPD.[2] It is unclear if use during pregnancy is safe for the baby.[4] Timolol is in the non-selective Beta blocker family of medication.[2]
Timolol was patented in 1968 and came into medical use in 1978.[5] It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system.[6] Timolol is available as a generic medication.[2] The wholesale cost in the developing world is about 0.86 to 2.29 USD per 5 ml bottle.[7] In the United States it costs 25 to 50 USD per month.[8]
Contents
Medical uses[edit]
By mouth[edit]
In its by mouth form, it is used:
- to treat high blood pressure
- to prevent heart attacks
- to prevent migraine headaches[9]
Eye drops[edit]
In its eye drop form it is used to treat open-angle and, occasionally, secondary glaucoma by reducing aqueous humour production through blockage of the β receptors on the ciliary epithelium. The pharmacological mechanism by which it actually does this is still unknown. It was the first β blocker approved for topical use in treatment of glaucoma in the USA (1978). When used by itself, it depresses intraocular pressure (IOP) 18–34% below baseline within first few treatments. However, there are short-term escape and long-term drift effects in some patients. That is, tolerance develops. It may reduce the extent of diurnal IOP curve up to 50%. IOP higher during sleep. It is 5–10× more potent β blocker than propranolol. Timolol is light-sensitive; it is usually preserved with 0.01% benzalkonium chloride (BAC), but also comes BAC-free. Can also be used in adjunctive therapy with pilocarpine or carbonic anhydrase inhibitors.[10]
A Cochrane Systematic Review compared the effect of timolol versus brimonidine in slowing the progression of open angle glaucoma in adult participants.[11]
Side effects[edit]
The most serious possible side effects include cardiac arrhythmias and severe bronchospasms. Timolol can also lead to fainting, congestive heart failure, depression, confusion, worsening of Raynaud's syndrome and impotence.
Side effects when given in the eye include: burning sensation, eye redness, superficial punctate keratopathy, corneal numbness.
Formulations[edit]
It is available in tablet and liquid formulations.
For ophthalmic use, timolol is also available combined:
- with carbonic anhydrase inhibitors:
- timolol and brinzolamide
- timolol and dorzolamide
- with α2 agonists:
- with prostaglandin analogs:
- timolol and latanoprost
- timolol and travoprost
Brand names[edit]
Timolol is marketed under many trade names worldwide.[1]
References[edit]
- ^ a b "Timolol - Drugs.com". www.drugs.com. Retrieved 28 December 2016.
- ^ a b c d e f "Timolol eent". The American Society of Health-System Pharmacists. Retrieved 8 December 2016.
- ^ a b c "Timolol Maleate". The American Society of Health-System Pharmacists. Retrieved 8 December 2016.
- ^ "Timolol ophthalmic Use During Pregnancy | Drugs.com". www.drugs.com. Retrieved 28 December 2016.
- ^ Fischer, Janos; Ganellin, C. Robin (2006). Analogue-based Drug Discovery. John Wiley & Sons. p. 460. ISBN 9783527607495.
- ^ "WHO Model List of Essential Medicines (19th List)" (PDF). World Health Organization. April 2015. Retrieved 8 December 2016.
- ^ "Timolol Maleate". International Drug Price Indicator Guide. Retrieved 8 December 2016.
- ^ Hamilton, Richart (2015). Tarascon Pocket Pharmacopoeia 2015 Deluxe Lab-Coat Edition. Jones & Bartlett Learning. p. 411. ISBN 9781284057560.
- ^ Dawn A. Marcus; Philip A. Bain (27 February 2009). Effective Migraine Treatment in Pregnant and Lactating Women: A Practical Guide. シュプリンガー・ジャパン株式会社. pp. 141–. ISBN 978-1-60327-438-8. Retrieved 14 November 2010.
- ^ Strohmaier, K; Snyder, E; Adamsons, I (Jul 1998). "A multicenter study comparing dorzolamide and pilocarpine as adjunctive therapy to timolol: patient preference and impact on daily life". J Am Optom Assoc. 69 (7): 441–51. PMID 9697378.
- ^ Sena DF, Lindsley K (2013). "Neuroprotection for treatment of glaucoma in adults". Cochrane Database Syst Rev. 2 (2): CD006539. doi:10.1002/14651858.CD006539.pub3. PMC 4261923
. PMID 23450569.
